Siemens SIMATIC ET 200AL, System Manual

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Communications services
3.6 Secure Communication
Communication
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Function Manual, 05/2021, A5E03735815-AJ
4. Set the parameters for secure communication in the "Start value" column.
– "ActivateSecureConn": Activation of secure communication for this connection. If this
parameter has the value FALSE, the subsequent security parameters are irrelevant. You
can set up a non-secure TCP or UDP connection in this case.
– "ExtTLSCapabilities": If you enter the value 1, the client validates the
subjectAlternateName in the X.509-V3 certificate of the server to verify the identity of
the server. This validation is executed in the context of the instruction.
– "TLSServerCertRef": ID of the X.509-V3 certificate (usually a CA certificate) that is used
by the TLS client to validate the TLS server authentication. If this parameter is 0, the
TLS client uses all (CA) certificates currently loaded in the client certificate store to
validate the server authentication.
Figure 3-19 Certificate handling from the perspective of the S7-1500 as a TLS client
– "TLSClientCertRef": ID of the own X.509-V3 certificate.